Daily Interest Calculator
Calculate simple daily interest on a balance. Enter the principal, annual interest rate, and number of days to see the interest earned or owed.
Recommended Settings
Pro Tips
- •This calculates simple interest, applying the daily rate uniformly across each day rather than compounding daily
- •The daily rate is calculated by dividing the annual rate by 365 - some institutions use 360 days instead, which would give a slightly different result
- •Daily interest calculations are common for short-term deposits, credit card balances, and per-diem loan interest
- •For interest that compounds daily rather than simply accruing, the actual balance would grow slightly faster than shown here
Most Popular
Most users calculate daily interest for short time periods like 30 or 90 days
When to Use This Tool
Estimate how much interest a savings balance earns over a specific number of days.
Calculate daily interest accrual on a loan balance, such as for a per-diem payoff amount.
Compare interest earned on short-term deposits held for varying numbers of days.
Understand how daily interest accrues on a carried credit card balance.
How It Works
Divide the annual interest rate by 365 to get the daily interest rate
Multiply the principal by the daily rate to get the daily interest amount
Multiply the daily interest by the number of days to get total interest, then add it to the principal for the final balance
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Frequently Asked Questions
Is this simple or compound interest?
This calculates simple interest, where the daily interest amount stays constant based on the original principal. It doesn't compound (interest earning interest), which would produce a slightly higher total over time.
Why 365 days instead of 360?
This tool uses a 365-day year, which is common for many savings and deposit accounts. Some loan products use a 360-day "banker's year" convention instead, which would result in a slightly higher daily rate.
Is my data sent to a server?
No. All calculations happen instantly in your browser using JavaScript. Nothing you enter is transmitted anywhere.
Can I use this for a loan I'm paying off?
Yes, the same simple interest formula applies whether you're earning interest on a deposit or owing interest on a loan - just interpret the "final balance" as what you'd owe rather than what you'd have.
How is this different from the Monthly Interest Calculator?
This tool calculates interest accrual per day, useful for short or irregular time periods. The Monthly Interest Calculator instead calculates interest on a monthly basis, which is more common for standard loan and savings statements.